Recent progress in clinical and laboratory investigations has shown that Human Umbilical Cord Blood (UCB) contains cells capable of sustained hematopoietic engraftment, and therefore UCB has vast potential as a source of hematopoietic stem cells for allogeneic and autologous bone marrow transplantation. UCB is particularly attractive because of the possibility that its use might decrease the incidence and severity of graft versus host disease, and thereby decrease overall post-transplant complications. UCB offers major theoretical benefits as a treatment for hemoglobinopathies, where the high disease incidence in non-Caucasian patients makes matched unrelated donor bone marrow searches problematic at present. Several issues need to be addressed however, before UCB can be routinely used as a transfusion product for stern cell support, including increasing the number of transplantable stem cells available from a given volume of UCB, and developing a UCB bank that maximizes the chances of banked UCB units to be used for clinical transplants. It is the intent of this project to attack these issues, with the goal of transforming UCB from an exotic research field to a routine blood bank transfusion therapy that will be of decisive benefit to common, serious diseases such as sickle cell anemia. In particular, we plan to develop a facility that will be tailored for correction of homozygous Sickle Cell Anemia by human umbilical cord blood cell transplantation. The program will both target our loco-regional population, heavily represented by African-Americans, and will serve as a national resource as well. To achieve this goal, we propose two Specific Aims: 1) To develop a HUCB bank targeted at the African-American population, emphasizing application towards correction of Sickle Cell Disease, and 2) To explore and develop techniques of HUCB stem cell expansion. Achieving these two goals should make major studies towards enabling the widespread cure of SS disease through HUCB transplantation.